Automatic coverslipper apparatus

ABSTRACT

Apparatus is described for applying a coverslip to a microscope slide wherein a coverslip is dispensed from a magazine, a predetermined amount of liquid is applied to a face of the coverslip, a microscope slide is positioned in close proximity to such face of the coverslip, and a portion of the coverslip is moved toward the microscope slide so that the liquid comes into contact with the slide and bridges a portion of the space between the coverslip and the slide. Capillary action of the liquid then acts to draw the coverslip against the slide. The liquid fills the space between the coverslip and slide and capillary action maintains all the liquid within such capillary space.

United States Patent [191 Johnson Sept. 3, 1974 AUTOMATIC COVERSLIPPER APPARATUS [75] Inventor: Leighton Clifford Johnson,

Edwardsburg, Mich.

22 Filed: Oct. 4, 1972 21 Appl.No.:295,007

[52] US. Cl 156/556, 156/572, 350/92 [51] Int. Cl. B32b 31/12, G02b 21/34 [58] Field of Search 156/556, 578, 72, 99, 145,

[56] References Cited UNITED STATES PATENTS 1,882,919 10/1932, Robbins 350/92 2,105,688 l/l938 Fessenden 156/57 2,801,568 8/1957 Dakin 350/92 1/1970 Howard ..156/556 4/1972 Bucher 156/99 Primary Examiner-Douglas J. Drummond [57] ABSTRACT Apparatus is described for applying a coverslip to a microscope slide wherein a coverslip is dispensed from a magazine, a predetermined amount of liquid is applied to a face of the coverslip, a microscope slide is positioned in close proximity to such face of the coverslip, and a portion of the coverslip is moved toward the microscope slide so that the liquid comes into contact with the slide and bridges a portion of the space between the coverslip and the slide. Capillary action of the liquid then acts to draw the coverslip against the slide. The liquid fills the space between the coverslip and slide and capillary action maintains all the liquid within such capillary space.

5 Claims, 7 Drawing Figures PAIENTEDSEP 3I974 3.833449 ME! 1 0F 2 95 A has 99 1 94- LIQUID SUPPLY CENTRAL APPARATUS CONTROL 7 v DISPENSER Ac A [G TU TOR erg Ea 7 2 FIGURE '2.

96 1 FIGURE 3.

CONVEYOR CENTRAL ACTUATOR CONWOL. /0/ I02 PATENIEDSEP 31914 2x'.'aa3.449

' sum 20F? FIGURE 4.

FIGURE 5.

AUTOMATIC COVERSLIPPER APPARATUS BACKGROUND AND PRIOR ART In the art of microscopy the specimens mounted on a microscope slide are frequently impregnated with a resin, such as a terpene polymer dissolved in toluene, and then covered with a flat transparent coverslip. This coverslipping technique accomplishes several purposes. First, the resin, which has a refractive index substantially the same as glass and cellular protein, impregnates the specimen and provides a clear unrefracted optical path through the speciment. Second, the coverslip, which is adhered to the specimen by the adhesive resin, provides an optically flat surfaceover the specimen. This is an advantage since many of the specimens have an irregular upper surface which presents focusing problems to the microscopist. Third, the coverslip and resin form a protective barrier over the specimen to shield the specimen from oxidation, microbial decay and physical damage.

In the prior art coverslipping was generally accomplished by the manual operations of applying the resin to the specimen on the microscope slide and then pressing a coverslip onto the resin. This technique usually forced some of the sticky resin out from the space between the coverslip and the slide, and this excess resin presented handling problems. Efforts have also been directed in the prior art toward mechanical apparatus for applying coverslips to slides. These efforts have not achieved commercial success because of their complexity and high cost.

SUMMARY OF THE INVENTION In accordance with the present invention apparatus is provided for adhering two flat-surfaced members in face-to-face relation comprising in combination means for applying apredetermined amount of liquidto a portion of the flat surface of one of said members; means for positioning said members with the flat surfaces thereof in closely spaced opposed relation such that said liquid initially contacts a portion only of each of the flat surfaces of saidmembers, the surface tension and capillary action of said liquid being effective to thereupon draw said flat surfaces together and cause said liquid to substantially till the thus reduced space between said surfaces, the amount of said liquid being not substantially in excess of that required to completely fill said reduced space.

In further accordance with the present invention apparatus is provided for applying a coverslip to a microscope slide which apparatus comprises in combination means for dispensing a coverslip having a flat surface, means for applying a predetermined amount of liquid to the flat surface of said coverslip, means for positioning a microscope slide in close proximity to the flat surface of said coverslipv to form a capillary space therebetween, and means for reducing the width of a portion of such capillary space so that the liquid on said coverslip comes into contact with said microscope slide and bridges a portion of such capillary space, the surface tension andthe capillary action of said liquid then acting to draw the coverslip against the microscope slide with the liquid filling the space therebetween, such capillary action also maintaining the liquid completely within such capillary space.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of apparatus of the present invention;

FIG. 2 is a side cross-sectional view of the apparatus of FIG. 1 taken along line 22;

FIG. 3 is an end elevation view of the apparatus of FIG. 1 taken along line 33;

FIG. 4 is a fragmentary side cross-sectional view similar to FIG. 2 showing a portion of the apparatus in one operational mode;

FIG. 5 is a fragmentary side cross-sectional view similar to FIG. 4 showing the illustrated portions of the apparatus in another operational mode;

FIG. 6 is an end elevation and partial cross-sectional view taken along line 6-6 of FIG. 5; and

FIG. 7 is a view similar to that of FIG. 6 showing the coverslip applied to the microscope slide.

DESCRIPTION OF THE INVENTION Referring to FIGS. 1 and 2, the apparatus of the present invention has a dispensing means 10 for dispensing a coverslip 12 from 'a magazine 14, a liquid outlet 16 connected to a liquid reservoir (not shown) for applying liquid to the uppersurface of the coverslip, rails 18 and 19 for supporting coverslip l2, rails 20 and 21 for supporting a microscope slide 22 above and. in close proximity to the coverslip l2 and spring-actuated means 24 for elevating a portion of the coverslip.

The dispenser 10-is in the form of a rod having an inclined lower end surface 28 and an upper cut-away portion forming a flat surface 26 and side projections 27 and 29. A bore 32 is located along flat surface 26 and is normal to the longitudinal axis of dispenser 10. A pawl 30, having a bore 36 formed in the underside thereof and'also having a threaded passage 38 therethrough, both normal to the longitudinal axis of pawl 30, is located above flat surface 26 and between the side projections 27 and 29 with bore 36 aligned with bore 32. A pivot pin 31 passes transversely through appropriately aligned passages in pawl and side projec tions 27 and 29. A helical compression spring 40 is located in and between bores 32 and 36 and forces the outer end of pawl 30 upward away from flat surface 26 by rotation of pawl 30 around pivot 31. A screw 42 is threaded into passage 38 and is capable of extending beyond passage 38 into contact with flat surface 26. The axial extension of the screw beyond passage 38 will determine the amount of rotation of pawl 30 around pivot 31 and thus the height of the outer end of pawl 30 above flat surface 26. Rotation of this screw can thus adjust the height of the outer end of pawl 30. Dispenser 10 is suitably mounted for reciprocating movement along its longitudinal axis and such movement is controlled by a dispenser actuator which is schematically shown by block 44 connected to dispenser 10 through line 46. Various mechanical means can be employed for this movement.

Magazine 14 is rectangular in shape having sidewalls 48. and and'endwalls 52 and 54. The sidewalls 48 and 50 have upper slots 55 and 56 therein and are formed with inwardly-projecting flanges 57 and 58 along the lower edges respectively thereof. Endwall 52 has a slot 60 formed in the lower edge thereof which extends above flanges 57 and 58. Endwall 54 has a slot 62 therein which extends from its lower edge upward about half the length of endwall 54. Slots 60 and 62 are each slightly wider than dispenser 10. A single .leaf spring 64 has one end attached to the outer surface of endwall 54 and extends downwardly into slot 62 as shown. The lower end portion 66 of spring 64 is located along a plane substantially parallel to the plane of the inner surface of endwall 54.

A plurality of flat rectangular transparent coverslips 12 can be placed inside magazine 14 and are supported on the flanges 57 and 58. End portion 66 of spring 64 is positioned so as to contact the adjacent end edge of the second coverslip 12a located within magazine 14. The height of the outer end of pawl 30 is adjusted by screw 42 so as to contact only the lower coverslip 12 in magazine 14 when the dispenser is located in the position shown. 7

The dispensing of liquid from outlet 16 is controlled by the liquid supply apparatus which is schematically shown by block 72 connected to outlet 16 through line 74. Various known means can be employed for this operation. The sequential operation of the dispenser actuator 44 and the liquid supply apparatus 72 is controlled by the central control schematically shown by block 76 connectedto blocks 44 and 72, respectively, by lines 78 and 80. Various known circuits can be employed for this function.

Rails 18 and 19 take the form of inturned flanges on the upper edges of vertical walls 84 and 85 which are in turn supported by base 86. Rails 18 and 19 are spaced apart a distance slightly less than the width of a coverslip l2. Elevating means 24 located between rails 18 and 19 is formed by an upwardly bent portion of an arm 88 of spring 90 which is mounted on base 86 as shown. Arm 88 also has a transversely bent horizontal arm portion 82. Elevating means 24 normally has the position shown in FIG. 2 where it projects above rails 18 and 19. 7

Rails 20 and 21 which are spaced apart a distance less than the length of a microscope slide 22 have substantially horizontal portions 92 and 93, respectively, located slightly above the plane of rails 18 and 19 and arcuate portions 94 and 95, respectively, extending beyond rails 18- and 19. This is shown in FIGS. 1 and 3. Conveyor arms 96 and 97, having upper lips 98 and99, respectively, are located in the space between rails 20 and 21 and are suitably mounted for rotatable movement around the axis of pivot 97; Conveyor arms 96 and 97 are capable of movement from the position shown in FIG. 3 up to and beyond horizontal portions 92 and 93 of rails 20 and 21. The movement of conveyor arms 96 and 97 is controlled by a conveyor actuator which is schematically shown by block 100 connected to conveyor arm 96 through line 101. The sequential operation of conveyor actuator 100 is controlled by the central control schematically shown by block 76 connected to block 100 by line 102. Various well-known mechanical means and circuits can be employed for this operation.

When dispenser 10 is moved along its longitudinal axis to the left, as viewed'in FIGS. 1 and 2, the outer end of pawl engages the lowermost coverslip 12 in magazine 14 and moves it out of the magazine 14 along flanges 57 and 58 and onto rails 18 and 19. Spring64 engages the. coverslips above the lowermost coverslip in magazine 14 and prevents them fromalso moving out of the magazine 14. As the lowermost coverslip is moved beneathliquid outlet 16, a predetermined dispensed from the outlet 16 onto the upper flat surface of the coverslip 12 (as shown in FIG. 4). The dispenser 10 then continues its axial movement toward the left until it reaches the position shown in FIG. 4. As the inclined surface 28 of dispenser 10 engages the transverse arm 82 of spring 90, it moves said arm downward thereby lowering the elevating means 24 to the position beneath the upper surfaces of rails 18 and 19 as shown in FIG. 4.

A microscope slide 22 to be coverslipped is placed on rails 20 and 21 in abutment with the lips 98 and 99 of conveyor arms 96 and 97 as shown in FIGS. 1 and 3. Either before, concurrently, or after the coverslip I2 is positioned over elevating means 24, as desired, the conveyor arms 96 and 97 are rotated upwardly; i.e., toward the left in FIG. 3, to move the microscope slide 22 along rails 20. and 21 to the position shown in the dot and dash lines in FIG. 3 and in the solid lines in FIG. 4. Once the conditions shown in FIG. 4 are achieved, the conveyor arms 96 and 97 are returned to the initial positions thereof shown in FIGS. 1 and 3, and the dispenser 10 begins return movement to the right as viewed in FIG. 4 to achieve the conditions shown in FIG. 5. During this return movement, arm portion 82 of spring 90 moves upward along the withdrawing inclined surface 28. This permits elevating means 24 to move upward to engage coverslip l2 and lift one edge thereof into capillary spacial relationship with the underside of slide 22 wherein liquid 68 contacts the microscope slide and bridges a portion of such capillary space. This is shown in FIGS. 5 and 6. The surface tension and capillary action of liquid 68 then acts to draw the coverslip l2 upwardly against the underside of the microscope slide 22 with the liquid 68 filling the space therebetween as shown in FIG. 7. This capillary action also maintains the liquid 68 completely within such capillary space and prevents the liquid from flowing out of the open edges of the capillary space.

The dispenser 10 then completes its return movement to the position thereof shown in FIGS. 1 and 2 and the coverslipped slide 22 is removed from the rails 20 and 21. Upon placement of a new microscope slide 22 on rails 20 and 21, the above operational cycle can berepeated.

The above-described apparatus can be used to automatically mount coverslips on microscope slides which are originally manually placed on rails 20 and 21. The central control 76 can be activated manually or by a suitable switch (not shown) positioned to be engaged by a slide placed on rails 20 and 21. The apparatus of the present invention can also be positioned at the outlet of a microscope slide staining apparatus so that as the staining operation is completed, the stained slides drop onto rails 20 and 21. The aforementioned actuating switch (not shown) could then activate the central control 76 for completely automatic operation.

If it is desired, after the coverslipping operation is completed, conveyor arms 96 and 97 could be made to continue their motion along rails 20 and 21 to convey the coverslipped-slide beyond the ends of said rails to a subsequent treating station (not shown), such as a dryer, before said arms are returned to their initial position.

amount of liquid 68, such as a coverslipping resin, is

that, in the event that coverslips are employed which 9 have the resin previously coated thereon, the liquid dispensed from outlet 16 could be a solvent for such resin.

The apparatus of the present invention has a principal advantage of automatic operation which frees laboratory technicians from the time-consuming chore of manually applying coverslips. It also has the advantages of providing desirable reproducible coverslipping conditions and eliminating the handling problems caused by excess coverslipping resin smearing the outsides of the coverslips and the slides. The apparatus is also less complex than those of the prior art.

What is claimed is:

1. Apparatus for applying a coverslip to a microscope slide which comprises in combination means for dispensing a coverslip having a flat surface, means for applying a predetermined amount of liquid to the flat surface of said coverslip, means for positioning a microscope slide in close proximity to the flat surface of said coverslip to form a capillary space therebetween, and means for reducing the width only of a portion of such capillary space so that the liquid on said coverslip comes into contact with said microscope slide and bridges a portion of such capillary space, the surface tension and the capillary action of said liquid then acting to draw the coverslip against the microscope slide with the liquid filling the space therebetween, such capillary action also maintaining the liquid completely within such capillary space.

2. Apparatus according to claim 1 wherein the liquid is applied to an upper surface of said coverslip and said microscope slide is positioned over said coverslip.

3. Apparatus according to claim 2 wherein the means for reducing the width of a portion of the capillary space comprises a means for elevating a portion of the coverslip.

4. Apparatus according to claim 3 wherein the means for elevating a portion of the coverslip is spring actuated.

5. Apparatus according to claim 1 also having a magazine for supplying coverslips to the means for dispensing such coverslips. 

1. Apparatus for applying a coverslip to a microscope slide which comprises in combination means for dispensing a coverslip having a flat surface, means for applying a predetermined amount of liquid to the flat surface of said coverslip, means for positioning a microscope slide in close proximity to the flat surface of said coverslip to form a capillary space therebetween, and means for reducing the width only of a portion of such capillary space so that the liquid on said coverslip comes into contact with said microscope slide and bridges a portion of such capillary space, the surface tension and the capillary action of said liquid then acting to draw the coverslip against the microscope slide with the liquid filling the space therebetween, such capillary action also maiNtaining the liquid completely within such capillary space.
 2. Apparatus according to claim 1 wherein the liquid is applied to an upper surface of said coverslip and said microscope slide is positioned over said coverslip.
 3. Apparatus according to claim 2 wherein the means for reducing the width of a portion of the capillary space comprises a means for elevating a portion of the coverslip.
 4. Apparatus according to claim 3 wherein the means for elevating a portion of the coverslip is spring actuated.
 5. Apparatus according to claim 1 also having a magazine for supplying coverslips to the means for dispensing such coverslips. 